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Alfvén's theorem

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455: 217:-like region of space containing a magnetic field such that its sides are everywhere parallel to the field. Consequently, the magnetic flux through these sides is zero, and the cross-sections along the tube's length have constant, equal magnetic flux. In the limit of a large magnetic Reynolds number, Alfvén's theorem requires that these surfaces of constant flux move with the fluid that they are embedded in. As such, magnetic flux tubes are frozen into the fluid. 167: 1602: 2723:
produces results equivalent to that of classical Alfvén's theorem under ideal conditions, while also describing flux conservation and magnetic reconnection under non-ideal (real-world) conditions. Thus stochastic flux-freezing solutions can provide better descriptions of observed phenomena without relying on idealized conditions that are rare or even absent in the observed environment.
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is a linear combination of the mean motions of the individual species weighted by the species' respective mass. Under Alfvén's theorem, the magnetic field is restricted to move with this bulk velocity, but not necessarily with the velocity of the individual species. As such, Alfvén's theorem does not
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The intersection of the sides of two magnetic flux tubes form a magnetic field line, a curve that is everywhere parallel to the magnetic field. In fluids where flux tubes are frozen-in, it then follows that magnetic field lines must also be frozen-in. However, the conditions for frozen-in field lines
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Research in the 21st century has claimed that the classical Alfvén theorem is inconsistent with the phenomenon of spontaneous stochasticity. Stochastic conservation laws developed to describe hydrodynamic behavior are shown to apply in the magnetohydrodynamic regime as well. Using the same tools
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Alfvén's theorem indicates that the magnetic field topology cannot change in a perfectly conducting fluid. However, in the case of complicated or turbulent flows, this would lead to highly tangled magnetic fields with very complicated topologies that should impede the fluid motions.
1597:{\displaystyle {\begin{aligned}{\frac {D\Phi _{B}}{Dt}}=\lim _{\delta t\to 0}\iint _{S_{1}}{\frac {\mathbf {B} (t+\delta t)-\mathbf {B} (t)}{\delta t}}\cdot d\mathbf {S} _{1}-\oint _{\partial S_{1}}\left(\mathbf {v} \times \mathbf {B} (t)\right)\cdot d\mathbf {l} .\end{aligned}}} 2689: 819: 2519: 556: 1617: 442: 2041: 148:. Magnetic flux conservation implies that the magnetic flux through a surface moving with the bulk fluid velocity is constant, and magnetic field line conservation implies that, if two fluid elements are connected by a magnetic field line, they will always be. 1840: 2262: 1335:{\displaystyle \iint _{S_{2}}\mathbf {B} (t+\delta t)\cdot d\mathbf {S} _{2}=\iint _{S_{1}}\mathbf {B} (t+\delta t)\cdot d\mathbf {S} _{1}-\oint _{\partial S_{1}}\left(\mathbf {v} \ \delta t\times \mathbf {B} (t)\right)\cdot d\mathbf {l} ,} 2899:
guarantee that individual species within the fluid will be restricted to move with the magnetic field, and currents can flow perpendicular to the magnetic field provided the bulk velocity matches the velocity of the magnetic field.
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are frozen to the fluid, analogous to how magnetic flux tubes moving with a perfectly conducting ideal-MHD fluid are frozen to the fluid. The ideal induction equation takes the same form as the equation for vorticity
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are infinitely large. Motions of the two are constrained in that all bulk fluid motions perpendicular to the magnetic field result in matching perpendicular motion of the field at the same velocity and vice versa.
2052: 2580: 1018:{\displaystyle 0=-\iint _{S_{1}}\mathbf {B} (t+\delta t)\cdot d\mathbf {S} _{1}+\iint _{S_{2}}\mathbf {B} (t+\delta t)\cdot d\mathbf {S} _{2}+\iint _{S_{3}}\mathbf {B} (t+\delta t)\cdot d\mathbf {S} _{3},} 2454: 739:{\displaystyle {\frac {D\Phi _{B}}{Dt}}=\lim _{\delta t\to 0}{\frac {\iint _{S_{2}}\mathbf {B} (t+\delta t)\cdot d\mathbf {S} _{2}-\iint _{S_{1}}\mathbf {B} (t)\cdot d\mathbf {S} _{1}}{\delta t}}.} 1756:{\displaystyle {\frac {D\Phi _{B}}{Dt}}=\iint _{S_{1}}\left({\frac {\partial \mathbf {B} }{\partial t}}-\nabla \times \left(\mathbf {v} \times \mathbf {B} \right)\right)\cdot d\mathbf {S} _{1}.} 1380: 373: 1963: 1817: 315: 447:
The conservation of magnetic flux through material surfaces embedded in the fluid follows directly from the ideal induction equation and the assumption of no magnetic monopoles through
96:"On the Existence of Electromagnetic-Hydrodynamic Waves" interpreted the results of Alfvén's earlier paper "Existence of Electromagnetic-Hydrodynamic Waves", published in the journal 1947:{\displaystyle {\frac {\partial \mathbf {B} }{\partial t}}=(\mathbf {B} \cdot \nabla )\mathbf {v} -(\mathbf {v} \cdot \nabla )\mathbf {B} -\mathbf {B} (\nabla \cdot \mathbf {v} ).} 88:
In view of the infinite conductivity, every motion (perpendicular to the field) of the liquid in relation to the lines of force is forbidden because it would give infinite
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Eyink, Gregory L.; Aluie, Hussein (November 2006). "The breakdown of Alfvén's theorem in ideal plasma flows: Necessary conditions and physical conjectures".
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In mathematical terms, Alfvén's theorem states that, in an electrically conducting fluid in the limit of a large magnetic Reynolds number, the magnetic flux
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Field line conservation can also be derived mathematically using the ideal induction equation, Gauss's law for magnetism, and the mass continuity equation.
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Formally, the connection between the movement of the fluid and the movement of the magnetic field is detailed in two primary results, often referred to as
2397:{\displaystyle \left({\frac {\partial \mathbf {B} }{\partial t}}-\nabla \times \left(\mathbf {v} \times \mathbf {B} \right)\right)\times \mathbf {B} =0,} 2744: 2921: 2558:. In fact, a very high electrical conductivity translates into high magnetic Reynolds numbers, which indicates that the plasma will be turbulent. 3266:
Eyink, Gregory; Aluie, Hussein (2006). "The breakdown of Alfvén's theorem in ideal plasma flows: Necessary conditions and physical conjectures".
3139: 2133:{\displaystyle {\frac {D}{Dt}}\left({\frac {\mathbf {B} }{\rho }}\right)=\left({\frac {\mathbf {B} }{\rho }}\cdot \nabla \right)\mathbf {v} .} 2854:.) The many virtual field-vectors that arrive at the same final point must be averaged to obtain the physical magnetic field at that point. 2684:{\displaystyle \nabla \times ({\bf {{w}\times {\bf {{B})=\eta \nabla ^{2}{\bf {{B}+\nabla \times ({\bf {{v}\times {\bf {{B}),}}}}}}}}}}} 80: 2554:
seems to occur in these plasmas unlike what would be expected from the flux freezing conditions. This has important implications for
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is then assumed to be small relative to the induction term and is neglected. The induction equation then reduces to its ideal form:
2514:{\displaystyle {\frac {\partial {\boldsymbol {\omega }}}{\partial t}}=\nabla \times (\mathbf {v} \times {\boldsymbol {\omega }}).} 758:
can be re expressed by applying Gauss's law for magnetism to assume that the magnetic flux through a closed surface formed by
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whereas, for flux to be conserved, the fluid must satisfy the stronger condition imposed by the ideal induction equation.
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that electrically conducting fluids and the magnetic fields within are constrained to move together in the limit of large
3152: 437:{\displaystyle {\frac {\partial \mathbf {B} }{\partial t}}=\nabla \times \left(\mathbf {v} \times \mathbf {B} \right).} 2036:{\displaystyle {\frac {\partial \rho }{\partial t}}+(\mathbf {v} \cdot \nabla )\rho =-\rho \nabla \cdot \mathbf {v} ,} 3069: 3415:
Eyink, Gregory (2009). "Stochastic line motion and stochastic flux conservation for nonideal hydromagnetic models".
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Blackman, Eric G (1 March 2013). "On deriving flux freezing in magnetohydrodynamics by direct differentiation".
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of a fluid in the limit of a large magnetic Reynolds number cannot change. This approximation breaks down in
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Wilmot-Smith, A. L.; Priest, E. R.; Horing, G. (2005). "Magnetic diffusion and the motion of field lines".
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in a 1943 paper titled "On the Existence of Electromagnetic-Hydrodynamic Waves", published in the journal
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are weaker than the conditions for frozen-in flux tubes, or, equivalently, for conservation of flux.
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Alfvén's theorem is frequently expressed in terms of magnetic flux tubes and magnetic field lines.
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This generalized theorem states that magnetic field lines of the fine-grained magnetic field
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However, the induction equation is linear, whereas there is a nonlinear relationship between
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Applying the definition of a partial derivative to the integrand of the first term, applying
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with high electrical conductivities do not generally show such complicated tangled fields.
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Lalescu, Cristian C.; Shi, Yi-Kang; Eyink, Gregory; Drivas, Theodore D.; Vishniac, Ethan;
8: 2707: 1350: 3483: 3385: 3332: 3289: 3198: 3108: 3002: 2955: 3469: 3453: 3424: 3371: 3344: 3301: 3275: 3210: 3184: 3120: 3094: 2967: 1608: 364: 360: 3497: 3458:"Inertial-Range Reconnection in Magnetohydrodynamic Turbulence and in the Solar Wind" 3397: 3246: 3148: 3124: 3116: 3065: 3037: 2868: 2735: 532:. The rate of change of the magnetic flux through the surface as it is advected from 363:
at the velocity and length scales being studied. The diffusion term in the governing
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is the velocity at the other end, the differential velocity between the two ends is
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In an electrically conducting fluid with a space- and time-dependent magnetic field
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has been used. Although, in some cases, this velocity field can be found using
253: 36: 3340: 3242: 2863: 3515: 2571: 2555: 55: 3010: 3501: 3401: 3028:. Astrophysics and Space Science Library. Vol. 427. pp. 101–142. 2711: 133: 89: 2986: 2942:
Alfvén, Hannes (1942). "Existence of Electromagnetic-Hydrodynamic Waves".
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Mathematically, for field lines to be frozen-in, the fluid must satisfy
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to the second term, and combining the resultant surface integrals gives
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Eyink, Gregory (2011). "Stochastic flux freezing and magnetic dynamo".
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Priest, E. (2016). "MHD Structures in Three-Dimensional Reconnection".
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points outwards from the enclosed volume. In the surface integral over
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are cross sections of a magnetic flux tube; the magnetic flux through
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The concept of magnetic fields being frozen into fluids with infinite
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are "frozen-in" to the stochastic trajectories solving the following
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is not infinite, a similar result can be obtained by defining the
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Later in life, Alfvén advised against the use of his own theorem.
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Informally, Alfvén's theorem refers to the fundamental result in
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which has the same form as the equation obtained previously for
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Using the ideal induction equation, the integrand vanishes, and
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the ideal induction equation can be further rearranged to give
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While flux conservation implies field line conservation (see
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where the final term was rewritten using the properties of
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In magnetohydrodynamics (MHD), the bulk velocity field
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are constrained to move together in the limit of large
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Gubbins, David; Herrero-Bervera, Emilio, eds. (2007).
3230: 2987:"On frozen-in field lines and field-line reconnection" 1830:
The ideal induction equation can be rewritten using a
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was taken. Substituting this into the expression for
1134: 822: 559: 376: 270: 2293:are initially parallel, they will remain parallel. 3062:Magnetic Reconnection: MHD Theory and Applications 2827: 2683: 2513: 2396: 2256: 2132: 2035: 1946: 1811: 1755: 1596: 1334: 1017: 738: 436: 309: 2665: 2645: 2610: 3513: 2710:equations, the existence and uniqueness of this 1414: 591: 3234:Encyclopedia of Geomagnetism and Paleomagnetism 2410: 2297: 3321:Geophysical & Astrophysical Fluid Dynamics 3147:. Taipei: Airiti Press Inc. pp. 173–176. 3064:(First ed.). Cambridge University Press. 151: 3226: 3224: 3059: 2717: 252:by a macroscopic, space- and time-dependent 2158:is the bulk plasma velocity at one end and 1812:{\displaystyle {\frac {D\Phi _{B}}{Dt}}=0.} 310:{\displaystyle {\frac {D\Phi _{B}}{Dt}}=0,} 3408: 3355: 3265: 3174: 3055: 3053: 2566:Even for the non-ideal case, in which the 1822: 3491: 3473: 3428: 3375: 3279: 3221: 3188: 3098: 2421:Kelvin's circulation theorem states that 500:, an arbitrary, orientable, open surface 224: 3084: 2929:Arkiv för matematik, astronomi och fysik 1116:. Solving for the surface integral over 1097:is the line element around the boundary 813:, this relationship can be expressed as 453: 165: 81:Arkiv för matematik, astronomi och fysik 3050: 2913: 2501: 2465: 3514: 3237:. Dordrecht: Springer. pp. 7–11. 3168: 3023: 2984: 2941: 2919: 2714:depends on the underlying conditions. 197:is equal to the magnetic flux through 3414: 3361: 3060:Priest, Eric; Forbes, Terry (2000). 2879: 2694:in which, instead of fluid velocity 1957:Using the mass continuity equation, 346: 47:, who put the idea forward in 1943. 3137: 2561: 1062:, the differential surface element 213:A magnetic flux tube is a tube- or 13: 2886: 2846:is the three-dimensional Gaussian 2639: 2620: 2584: 2574:transporting velocity by writing: 2483: 2471: 2461: 2343: 2331: 2321: 2243: 2114: 2019: 2001: 1978: 1970: 1927: 1905: 1880: 1857: 1847: 1783: 1698: 1686: 1676: 1628: 1529: 1390: 1262: 567: 402: 390: 380: 278: 50:Alfvén's theorem implies that the 14: 3533: 2298:§ Flux tubes and field lines 1834:and Gauss's law for magnetism as 2811: 2773: 2763: 2753: 2732:stochastic differential equation 2668: 2661: 2651: 2636: 2632: 2624: 2613: 2606: 2596: 2493: 2381: 2363: 2355: 2325: 2250: 2236: 2211: 2123: 2102: 2078: 2026: 1994: 1934: 1920: 1912: 1898: 1887: 1873: 1851: 1740: 1718: 1710: 1680: 1583: 1558: 1550: 1511: 1479: 1453: 1325: 1300: 1283: 1244: 1214: 1183: 1153: 1002: 972: 941: 911: 880: 850: 785:that connects the boundaries of 712: 691: 660: 630: 422: 414: 384: 146:magnetic field line conservation 115:ideal magnetohydrodynamic theory 3445: 3417:Journal of Mathematical Physics 3312: 3259: 3141:Elementary Space Plasma Physics 2991:Journal of Geophysical Research 2540: 16:Theorem in magnetohydrodynamics 3493:10.1103/PhysRevLett.115.025001 3268:Physica D: Nonlinear Phenomena 3177:Physica D: Nonlinear Phenomena 3131: 3078: 3017: 2978: 2935: 2822: 2816: 2784: 2768: 2590: 2505: 2489: 2246: 2229: 2143:Similarly, for a line segment 2004: 1990: 1938: 1924: 1908: 1894: 1883: 1869: 1568: 1562: 1489: 1483: 1472: 1457: 1424: 1310: 1304: 1233: 1218: 1172: 1157: 991: 976: 930: 915: 869: 854: 701: 695: 649: 634: 601: 33:electrically conducting fluids 1: 2906: 458:The closed surface formed by 128:—such as when the fluid is a 2842:is magnetic diffusivity and 2417:Kelvin's circulation theorem 2411:Kelvin's circulation theorem 7: 3298:10.1016/j.physd.2006.08.009 3207:10.1016/j.physd.2006.08.009 3087:European Journal of Physics 3034:10.1007/978-3-319-26432-5_3 2857: 2537:in the vorticity equation. 1369:and simplifying results in 119:magnetic Reynolds numbers ( 108: 10: 3538: 3394:10.1103/PhysRevE.83.056405 3117:10.1088/0143-0807/34/2/489 2985:Alfvén, H. (August 1976). 2414: 749:The surface integral over 353:ideal magnetohydrodynamics 155: 152:Flux tubes and field lines 142:magnetic flux conservation 65: 21:ideal magnetohydrodynamics 3341:10.1080/03091920500044808 3243:10.1007/978-1-4020-4423-6 2718:Stochastic Alfvén theorem 1351:first-order approximation 449:Gauss's law for magnetism 41:magnetic Reynolds numbers 3138:Lyu, Ling-Hsiao (2010). 2442:in an ideal fluid where 3462:Physical Review Letters 3011:10.1029/JA081i022p04019 2920:Alfvén, Hannes (1943). 2448:is the velocity field: 1823:Field line conservation 72:electrical conductivity 2829: 2685: 2515: 2398: 2258: 2134: 2037: 1948: 1813: 1757: 1598: 1347:scalar triple products 1336: 1019: 740: 485: 438: 311: 225:Mathematical statement 207: 94: 74:was first proposed by 29:frozen-in flux theorem 3026:Magnetic Reconnection 2830: 2686: 2568:electric conductivity 2552:Magnetic reconnection 2548:Astrophysical plasmas 2516: 2415:Further information: 2399: 2259: 2135: 2038: 1949: 1814: 1758: 1599: 1337: 1041:was reversed so that 1020: 741: 457: 439: 312: 169: 156:Further information: 132:or when velocity and 86: 60:magnetic reconnection 3522:Magnetohydrodynamics 2745: 2700:, the flux velocity 2581: 2455: 2310: 2198: 2053: 1964: 1841: 1773: 1618: 1376: 1132: 820: 557: 374: 341:advective derivative 268: 43:. It is named after 3484:2015PhRvL.115b5001L 3386:2011PhRvE..83e6405E 3333:2005GApFD..99..177W 3290:2006PhyD..223...82E 3199:2006PhyD..223...82E 3109:2013EJPh...34..489B 3003:1976JGR....81.4019A 2956:1942Natur.150..405A 2708:magnetohydrodynamic 494:and velocity field 2825: 2681: 2511: 2394: 2254: 2130: 2033: 1944: 1809: 1753: 1594: 1592: 1431: 1332: 1015: 776:, and the surface 736: 608: 486: 434: 365:induction equation 361:magnetic diffusion 357:magnetic induction 307: 208: 3439:10.1063/1.3193681 3364:Physical Review E 3252:978-1-4020-3992-8 3043:978-3-319-26430-1 2997:(22): 4019–4021. 2880:Explanatory notes 2869:Magnetic pressure 2804: 2736:Langevin equation 2478: 2437:= ∇ × 2338: 2224: 2109: 2085: 2069: 1985: 1864: 1801: 1693: 1646: 1501: 1413: 1408: 1289: 803:is zero. At time 731: 590: 585: 397: 347:Flux conservation 329:= ∂/∂ 296: 130:perfect conductor 52:magnetic topology 3529: 3506: 3505: 3495: 3477: 3449: 3443: 3442: 3432: 3412: 3406: 3405: 3379: 3359: 3353: 3352: 3316: 3310: 3309: 3283: 3263: 3257: 3256: 3228: 3219: 3218: 3192: 3172: 3166: 3165: 3163: 3161: 3146: 3135: 3129: 3128: 3102: 3082: 3076: 3075: 3057: 3048: 3047: 3021: 3015: 3014: 2982: 2976: 2975: 2964:10.1038/150405d0 2939: 2933: 2932: 2926: 2917: 2900: 2897: 2890: 2874:Magnetic tension 2845: 2841: 2834: 2832: 2831: 2826: 2815: 2814: 2805: 2797: 2777: 2776: 2767: 2766: 2757: 2756: 2729: 2705: 2699: 2690: 2688: 2687: 2682: 2680: 2679: 2678: 2677: 2676: 2675: 2674: 2673: 2672: 2671: 2664: 2654: 2635: 2628: 2627: 2609: 2599: 2562:Resistive fluids 2556:magnetic dynamos 2536: 2530: 2520: 2518: 2517: 2512: 2504: 2496: 2479: 2477: 2469: 2468: 2459: 2447: 2441: 2403: 2401: 2400: 2395: 2384: 2376: 2372: 2371: 2367: 2366: 2358: 2339: 2337: 2329: 2328: 2319: 2292: 2286: 2278:. Therefore, if 2277: 2263: 2261: 2260: 2255: 2253: 2239: 2225: 2223: 2215: 2214: 2202: 2190: 2186:⋅ ∇) 2170: 2157: 2151: 2139: 2137: 2136: 2131: 2126: 2121: 2117: 2110: 2105: 2100: 2090: 2086: 2081: 2076: 2070: 2068: 2057: 2042: 2040: 2039: 2034: 2029: 1997: 1986: 1984: 1976: 1968: 1953: 1951: 1950: 1945: 1937: 1923: 1915: 1901: 1890: 1876: 1865: 1863: 1855: 1854: 1845: 1818: 1816: 1815: 1810: 1802: 1800: 1792: 1791: 1790: 1777: 1762: 1760: 1759: 1754: 1749: 1748: 1743: 1731: 1727: 1726: 1722: 1721: 1713: 1694: 1692: 1684: 1683: 1674: 1667: 1666: 1665: 1664: 1647: 1645: 1637: 1636: 1635: 1622: 1603: 1601: 1600: 1595: 1593: 1586: 1575: 1571: 1561: 1553: 1543: 1542: 1541: 1540: 1520: 1519: 1514: 1502: 1500: 1492: 1482: 1456: 1450: 1448: 1447: 1446: 1445: 1430: 1409: 1407: 1399: 1398: 1397: 1384: 1368: 1341: 1339: 1338: 1333: 1328: 1317: 1313: 1303: 1287: 1286: 1276: 1275: 1274: 1273: 1253: 1252: 1247: 1217: 1212: 1211: 1210: 1209: 1192: 1191: 1186: 1156: 1151: 1150: 1149: 1148: 1124: 1115: 1106: 1096: 1087: 1061: 1052: 1040: 1024: 1022: 1021: 1016: 1011: 1010: 1005: 975: 970: 969: 968: 967: 950: 949: 944: 914: 909: 908: 907: 906: 889: 888: 883: 853: 848: 847: 846: 845: 812: 802: 793: 784: 775: 766: 757: 745: 743: 742: 737: 732: 730: 722: 721: 720: 715: 694: 689: 688: 687: 686: 669: 668: 663: 633: 628: 627: 626: 625: 610: 607: 586: 584: 576: 575: 574: 561: 549: 540: 531: 522: 519:in a small time 518: 512: 508: 499: 493: 484: 475: 466: 443: 441: 440: 435: 430: 426: 425: 417: 398: 396: 388: 387: 378: 338: 337:⋅ ∇) 316: 314: 313: 308: 297: 295: 287: 286: 285: 272: 261:is constant, or 260: 247:material surface 237: 205: 196: 187: 178: 25:Alfvén's theorem 3537: 3536: 3532: 3531: 3530: 3528: 3527: 3526: 3512: 3511: 3510: 3509: 3450: 3446: 3413: 3409: 3360: 3356: 3317: 3313: 3281:physics/0607073 3264: 3260: 3253: 3229: 3222: 3190:physics/0607073 3173: 3169: 3159: 3157: 3155: 3144: 3136: 3132: 3083: 3079: 3072: 3058: 3051: 3044: 3022: 3018: 2983: 2979: 2940: 2936: 2924: 2918: 2914: 2909: 2904: 2903: 2893: 2891: 2887: 2882: 2860: 2843: 2839: 2810: 2809: 2796: 2772: 2771: 2762: 2761: 2752: 2751: 2746: 2743: 2742: 2734:, known as the 2727: 2720: 2701: 2695: 2660: 2659: 2658: 2650: 2649: 2648: 2631: 2630: 2629: 2623: 2619: 2605: 2604: 2603: 2595: 2594: 2593: 2582: 2579: 2578: 2564: 2543: 2532: 2526:∇ × 2525: 2500: 2492: 2470: 2464: 2460: 2458: 2456: 2453: 2452: 2443: 2431: 2425:moving with an 2419: 2413: 2380: 2362: 2354: 2353: 2349: 2330: 2324: 2320: 2318: 2317: 2313: 2311: 2308: 2307: 2288: 2279: 2269: 2249: 2235: 2216: 2210: 2203: 2201: 2199: 2196: 2195: 2172: 2159: 2153: 2144: 2122: 2101: 2099: 2098: 2094: 2077: 2075: 2071: 2061: 2056: 2054: 2051: 2050: 2025: 1993: 1977: 1969: 1967: 1965: 1962: 1961: 1933: 1919: 1911: 1897: 1886: 1872: 1856: 1850: 1846: 1844: 1842: 1839: 1838: 1832:vector identity 1825: 1793: 1786: 1782: 1778: 1776: 1774: 1771: 1770: 1744: 1739: 1738: 1717: 1709: 1708: 1704: 1685: 1679: 1675: 1673: 1672: 1668: 1660: 1656: 1655: 1651: 1638: 1631: 1627: 1623: 1621: 1619: 1616: 1615: 1609:Stokes' theorem 1591: 1590: 1582: 1557: 1549: 1548: 1544: 1536: 1532: 1528: 1524: 1515: 1510: 1509: 1493: 1478: 1452: 1451: 1449: 1441: 1437: 1436: 1432: 1417: 1400: 1393: 1389: 1385: 1383: 1379: 1377: 1374: 1373: 1363: 1354: 1324: 1299: 1282: 1281: 1277: 1269: 1265: 1261: 1257: 1248: 1243: 1242: 1213: 1205: 1201: 1200: 1196: 1187: 1182: 1181: 1152: 1144: 1140: 1139: 1135: 1133: 1130: 1129: 1123: 1117: 1114: 1108: 1107:of the surface 1105: 1098: 1089: 1072: 1063: 1060: 1054: 1051: 1042: 1039: 1033: 1006: 1001: 1000: 971: 963: 959: 958: 954: 945: 940: 939: 910: 902: 898: 897: 893: 884: 879: 878: 849: 841: 837: 836: 832: 821: 818: 817: 804: 801: 795: 792: 786: 783: 777: 774: 768: 765: 759: 756: 750: 723: 716: 711: 710: 690: 682: 678: 677: 673: 664: 659: 658: 629: 621: 617: 616: 612: 611: 609: 594: 577: 570: 566: 562: 560: 558: 555: 554: 548: 542: 539: 533: 530: 524: 523:to the surface 520: 514: 513:is advected by 510: 507: 501: 495: 489: 483: 477: 474: 468: 465: 459: 421: 413: 412: 408: 389: 383: 379: 377: 375: 372: 371: 359:dominates over 349: 321: 288: 281: 277: 273: 271: 269: 266: 265: 256: 236: 230: 227: 204: 198: 195: 189: 186: 180: 177: 171: 164: 154: 124: 111: 68: 37:magnetic fields 17: 12: 11: 5: 3535: 3525: 3524: 3508: 3507: 3454:Lazarian, Alex 3444: 3407: 3354: 3327:(2): 177–197. 3311: 3258: 3251: 3220: 3167: 3154:978-9868270954 3153: 3130: 3093:(2): 489–494. 3077: 3070: 3049: 3042: 3016: 2977: 2934: 2931:. 29B(2): 1–7. 2911: 2910: 2908: 2905: 2902: 2901: 2884: 2883: 2881: 2878: 2877: 2876: 2871: 2866: 2859: 2856: 2852:Wiener process 2836: 2835: 2824: 2821: 2818: 2813: 2808: 2803: 2800: 2795: 2792: 2789: 2786: 2783: 2780: 2775: 2770: 2765: 2760: 2755: 2750: 2719: 2716: 2692: 2691: 2670: 2667: 2663: 2657: 2653: 2647: 2644: 2641: 2638: 2634: 2626: 2622: 2618: 2615: 2612: 2608: 2602: 2598: 2592: 2589: 2586: 2563: 2560: 2542: 2539: 2522: 2521: 2510: 2507: 2503: 2499: 2495: 2491: 2488: 2485: 2482: 2476: 2473: 2467: 2463: 2412: 2409: 2405: 2404: 2393: 2390: 2387: 2383: 2379: 2375: 2370: 2365: 2361: 2357: 2352: 2348: 2345: 2342: 2336: 2333: 2327: 2323: 2316: 2266: 2265: 2252: 2248: 2245: 2242: 2238: 2234: 2231: 2228: 2222: 2219: 2213: 2209: 2206: 2141: 2140: 2129: 2125: 2120: 2116: 2113: 2108: 2104: 2097: 2093: 2089: 2084: 2080: 2074: 2067: 2064: 2060: 2044: 2043: 2032: 2028: 2024: 2021: 2018: 2015: 2012: 2009: 2006: 2003: 2000: 1996: 1992: 1989: 1983: 1980: 1975: 1972: 1955: 1954: 1943: 1940: 1936: 1932: 1929: 1926: 1922: 1918: 1914: 1910: 1907: 1904: 1900: 1896: 1893: 1889: 1885: 1882: 1879: 1875: 1871: 1868: 1862: 1859: 1853: 1849: 1824: 1821: 1820: 1819: 1808: 1805: 1799: 1796: 1789: 1785: 1781: 1764: 1763: 1752: 1747: 1742: 1737: 1734: 1730: 1725: 1720: 1716: 1712: 1707: 1703: 1700: 1697: 1691: 1688: 1682: 1678: 1671: 1663: 1659: 1654: 1650: 1644: 1641: 1634: 1630: 1626: 1605: 1604: 1589: 1585: 1581: 1578: 1574: 1570: 1567: 1564: 1560: 1556: 1552: 1547: 1539: 1535: 1531: 1527: 1523: 1518: 1513: 1508: 1505: 1499: 1496: 1491: 1488: 1485: 1481: 1477: 1474: 1471: 1468: 1465: 1462: 1459: 1455: 1444: 1440: 1435: 1429: 1426: 1423: 1420: 1416: 1412: 1406: 1403: 1396: 1392: 1388: 1382: 1381: 1359: 1343: 1342: 1331: 1327: 1323: 1320: 1316: 1312: 1309: 1306: 1302: 1298: 1295: 1292: 1285: 1280: 1272: 1268: 1264: 1260: 1256: 1251: 1246: 1241: 1238: 1235: 1232: 1229: 1226: 1223: 1220: 1216: 1208: 1204: 1199: 1195: 1190: 1185: 1180: 1177: 1174: 1171: 1168: 1165: 1162: 1159: 1155: 1147: 1143: 1138: 1121: 1112: 1103: 1070: 1058: 1049: 1037: 1026: 1025: 1014: 1009: 1004: 999: 996: 993: 990: 987: 984: 981: 978: 974: 966: 962: 957: 953: 948: 943: 938: 935: 932: 929: 926: 923: 920: 917: 913: 905: 901: 896: 892: 887: 882: 877: 874: 871: 868: 865: 862: 859: 856: 852: 844: 840: 835: 831: 828: 825: 799: 790: 781: 772: 763: 754: 747: 746: 735: 729: 726: 719: 714: 709: 706: 703: 700: 697: 693: 685: 681: 676: 672: 667: 662: 657: 654: 651: 648: 645: 642: 639: 636: 632: 624: 620: 615: 606: 603: 600: 597: 593: 589: 583: 580: 573: 569: 565: 546: 537: 528: 505: 481: 472: 463: 445: 444: 433: 429: 424: 420: 416: 411: 407: 404: 401: 395: 392: 386: 382: 348: 345: 318: 317: 306: 303: 300: 294: 291: 284: 280: 276: 254:velocity field 232: 226: 223: 202: 193: 184: 175: 153: 150: 122: 110: 107: 67: 64: 56:current sheets 31:, states that 15: 9: 6: 4: 3: 2: 3534: 3523: 3520: 3519: 3517: 3503: 3499: 3494: 3489: 3485: 3481: 3476: 3471: 3468:(2): 025001. 3467: 3463: 3459: 3455: 3448: 3440: 3436: 3431: 3426: 3423:(8): 083102. 3422: 3418: 3411: 3403: 3399: 3395: 3391: 3387: 3383: 3378: 3373: 3370:(5): 056405. 3369: 3365: 3358: 3350: 3346: 3342: 3338: 3334: 3330: 3326: 3322: 3315: 3307: 3303: 3299: 3295: 3291: 3287: 3282: 3277: 3273: 3269: 3262: 3254: 3248: 3244: 3240: 3236: 3235: 3227: 3225: 3216: 3212: 3208: 3204: 3200: 3196: 3191: 3186: 3182: 3178: 3171: 3156: 3150: 3143: 3142: 3134: 3126: 3122: 3118: 3114: 3110: 3106: 3101: 3096: 3092: 3088: 3081: 3073: 3071:0-521-48179-1 3067: 3063: 3056: 3054: 3045: 3039: 3035: 3031: 3027: 3020: 3012: 3008: 3004: 3000: 2996: 2992: 2988: 2981: 2973: 2969: 2965: 2961: 2957: 2953: 2950:(3805): 405. 2949: 2945: 2938: 2930: 2923: 2916: 2912: 2896: 2889: 2885: 2875: 2872: 2870: 2867: 2865: 2862: 2861: 2855: 2853: 2849: 2819: 2806: 2801: 2798: 2793: 2790: 2787: 2781: 2778: 2758: 2748: 2741: 2740: 2739: 2737: 2733: 2724: 2715: 2713: 2709: 2704: 2698: 2655: 2642: 2616: 2600: 2587: 2577: 2576: 2575: 2573: 2572:magnetic flux 2569: 2559: 2557: 2553: 2549: 2538: 2535: 2529: 2508: 2497: 2486: 2480: 2474: 2451: 2450: 2449: 2446: 2440: 2436: 2435: 2428: 2424: 2418: 2408: 2391: 2388: 2385: 2377: 2373: 2368: 2359: 2350: 2346: 2340: 2334: 2314: 2306: 2305: 2304: 2301: 2299: 2294: 2291: 2285: 2282: 2276: 2272: 2240: 2232: 2226: 2220: 2217: 2207: 2204: 2194: 2193: 2192: 2189: 2185: 2182: 2178: 2175: 2169: 2166: 2162: 2156: 2150: 2147: 2127: 2118: 2111: 2106: 2095: 2091: 2087: 2082: 2072: 2065: 2062: 2058: 2049: 2048: 2047: 2030: 2022: 2016: 2013: 2010: 2007: 1998: 1987: 1981: 1973: 1960: 1959: 1958: 1941: 1930: 1916: 1902: 1891: 1877: 1866: 1860: 1837: 1836: 1835: 1833: 1828: 1806: 1803: 1797: 1794: 1787: 1779: 1769: 1768: 1767: 1750: 1745: 1735: 1732: 1728: 1723: 1714: 1705: 1701: 1695: 1689: 1669: 1661: 1657: 1652: 1648: 1642: 1639: 1632: 1624: 1614: 1613: 1612: 1610: 1587: 1579: 1576: 1572: 1565: 1554: 1545: 1537: 1533: 1525: 1521: 1516: 1506: 1503: 1497: 1494: 1486: 1475: 1469: 1466: 1463: 1460: 1442: 1438: 1433: 1427: 1421: 1418: 1410: 1404: 1401: 1394: 1386: 1372: 1371: 1370: 1367: 1362: 1357: 1352: 1348: 1329: 1321: 1318: 1314: 1307: 1296: 1293: 1290: 1278: 1270: 1266: 1258: 1254: 1249: 1239: 1236: 1230: 1227: 1224: 1221: 1206: 1202: 1197: 1193: 1188: 1178: 1175: 1169: 1166: 1163: 1160: 1145: 1141: 1136: 1128: 1127: 1126: 1120: 1111: 1102: 1095: 1092: 1086: 1083: 1079: 1076: 1069: 1066: 1057: 1048: 1045: 1036: 1031: 1012: 1007: 997: 994: 988: 985: 982: 979: 964: 960: 955: 951: 946: 936: 933: 927: 924: 921: 918: 903: 899: 894: 890: 885: 875: 872: 866: 863: 860: 857: 842: 838: 833: 829: 826: 823: 816: 815: 814: 811: 807: 798: 789: 780: 771: 762: 753: 733: 727: 724: 717: 707: 704: 698: 683: 679: 674: 670: 665: 655: 652: 646: 643: 640: 637: 622: 618: 613: 604: 598: 595: 587: 581: 578: 571: 563: 553: 552: 551: 545: 536: 527: 517: 504: 498: 492: 480: 471: 462: 456: 452: 450: 431: 427: 418: 409: 405: 399: 393: 370: 369: 368: 366: 362: 358: 354: 344: 342: 336: 332: 328: 324: 304: 301: 298: 292: 289: 282: 274: 264: 263: 262: 259: 255: 251: 248: 245: 241: 235: 222: 218: 216: 211: 201: 192: 183: 174: 168: 163: 159: 149: 147: 143: 138: 135: 134:length scales 131: 127: 125: 116: 106: 103: 101: 100: 93: 91: 90:eddy currents 85: 83: 82: 77: 76:Hannes Alfvén 73: 63: 61: 57: 53: 48: 46: 45:Hannes Alfvén 42: 38: 35:and embedded 34: 30: 26: 22: 3465: 3461: 3447: 3420: 3416: 3410: 3367: 3363: 3357: 3324: 3320: 3314: 3271: 3267: 3261: 3233: 3183:(1): 82–92. 3180: 3176: 3170: 3158:. Retrieved 3140: 3133: 3090: 3086: 3080: 3061: 3025: 3019: 2994: 2990: 2980: 2947: 2943: 2937: 2928: 2915: 2894: 2888: 2837: 2725: 2721: 2712:vector field 2702: 2696: 2693: 2565: 2544: 2541:Implications 2533: 2527: 2523: 2444: 2438: 2433: 2432: 2423:vortex tubes 2420: 2406: 2302: 2295: 2289: 2283: 2280: 2274: 2270: 2267: 2187: 2183: 2180: 2176: 2173: 2167: 2164: 2160: 2154: 2148: 2145: 2142: 2045: 1956: 1829: 1826: 1765: 1606: 1365: 1360: 1355: 1344: 1118: 1109: 1100: 1093: 1090: 1084: 1081: 1077: 1074: 1067: 1064: 1055: 1046: 1043: 1034: 1027: 809: 805: 796: 787: 778: 769: 760: 751: 748: 543: 534: 525: 515: 502: 496: 490: 487: 478: 469: 460: 446: 350: 334: 330: 326: 322: 319: 257: 233: 228: 219: 212: 209: 199: 190: 181: 172: 145: 141: 139: 120: 112: 104: 98: 95: 87: 84:. He wrote: 79: 69: 49: 28: 24: 18: 2864:Alfvén wave 2848:white noise 2427:ideal fluid 1125:then gives 238:through an 62:can occur. 3475:1503.00509 3160:12 January 2907:References 2850:(see also 1028:where the 240:orientable 162:Field line 3430:0812.0153 3377:1008.4959 3274:(1): 82. 3125:119247916 3100:1301.3562 2838:in which 2802:η 2656:× 2643:× 2640:∇ 2621:∇ 2617:η 2601:× 2588:× 2585:∇ 2502:ω 2498:× 2487:× 2484:∇ 2472:∂ 2466:ω 2462:∂ 2378:× 2360:× 2347:× 2344:∇ 2341:− 2332:∂ 2322:∂ 2244:∇ 2241:⋅ 2233:δ 2208:δ 2115:∇ 2112:⋅ 2107:ρ 2083:ρ 2023:⋅ 2020:∇ 2017:ρ 2014:− 2008:ρ 2002:∇ 1999:⋅ 1979:∂ 1974:ρ 1971:∂ 1931:⋅ 1928:∇ 1917:− 1906:∇ 1903:⋅ 1892:− 1881:∇ 1878:⋅ 1858:∂ 1848:∂ 1784:Φ 1733:⋅ 1715:× 1702:× 1699:∇ 1696:− 1687:∂ 1677:∂ 1653:∬ 1629:Φ 1577:⋅ 1555:× 1530:∂ 1526:∮ 1522:− 1504:⋅ 1495:δ 1476:− 1467:δ 1434:∬ 1425:→ 1419:δ 1391:Φ 1319:⋅ 1297:× 1291:δ 1263:∂ 1259:∮ 1255:− 1237:⋅ 1228:δ 1198:∬ 1176:⋅ 1167:δ 1137:∬ 995:⋅ 986:δ 956:∬ 934:⋅ 925:δ 895:∬ 873:⋅ 864:δ 834:∬ 830:− 725:δ 705:⋅ 675:∬ 671:− 653:⋅ 644:δ 614:∬ 602:→ 596:δ 568:Φ 419:× 406:× 403:∇ 391:∂ 381:∂ 279:Φ 170:Surfaces 158:Flux tube 102:in 1942. 27:, or the 3516:Category 3502:26207472 3456:(2015). 3402:21728673 3349:51997635 3306:16529234 3215:16529234 2858:See also 550:is then 509:at time 250:advected 215:cylinder 109:Overview 58:, where 3480:Bibcode 3382:Bibcode 3329:Bibcode 3286:Bibcode 3195:Bibcode 3105:Bibcode 2999:Bibcode 2972:4072220 2952:Bibcode 1099:∂ 1085:δt 1080:× 810:δt 521:δt 339:is the 66:History 3500:  3400:  3347:  3304:  3249:  3213:  3151:  3123:  3068:  3040:  2970:  2944:Nature 2840:η 2434:ω 2281:δ 2275:ρ 2181:δ 2174:δ 2165:δ 2152:where 2146:δ 1358:Φ 1349:and a 1288:  1088:where 476:, and 320:where 231:Φ 99:Nature 3470:arXiv 3425:arXiv 3372:arXiv 3345:S2CID 3302:S2CID 3276:arXiv 3211:S2CID 3185:arXiv 3145:(PDF) 3121:S2CID 3095:arXiv 2968:S2CID 2925:(PDF) 1030:sense 3498:PMID 3398:PMID 3247:ISBN 3162:2023 3149:ISBN 3066:ISBN 3038:ISBN 2531:and 2287:and 2191:and 794:and 244:open 179:and 160:and 144:and 3488:doi 3466:115 3435:doi 3390:doi 3337:doi 3294:doi 3272:223 3239:doi 3203:doi 3181:223 3113:doi 3030:doi 3007:doi 2960:doi 2948:150 2179:= ( 1415:lim 1032:of 592:lim 541:to 351:In 333:+ ( 19:In 3518:: 3496:. 3486:. 3478:. 3464:. 3460:. 3433:. 3421:50 3419:. 3396:. 3388:. 3380:. 3368:83 3366:. 3343:. 3335:. 3325:99 3323:. 3300:. 3292:. 3284:. 3270:. 3245:. 3223:^ 3209:. 3201:. 3193:. 3179:. 3119:. 3111:. 3103:. 3091:34 3089:. 3052:^ 3036:. 3005:. 2995:81 2993:. 2989:. 2966:. 2958:. 2946:. 2927:. 2738:: 2163:+ 1807:0. 1366:Dt 1073:= 808:+ 767:, 467:, 451:. 355:, 343:. 327:Dt 242:, 23:, 3504:. 3490:: 3482:: 3472:: 3441:. 3437:: 3427:: 3404:. 3392:: 3384:: 3374:: 3351:. 3339:: 3331:: 3308:. 3296:: 3288:: 3278:: 3255:. 3241:: 3217:. 3205:: 3197:: 3187:: 3164:. 3127:. 3115:: 3107:: 3097:: 3074:. 3046:. 3032:: 3013:. 3009:: 3001:: 2974:. 2962:: 2954:: 2895:v 2844:W 2823:) 2820:t 2817:( 2812:W 2807:d 2799:2 2794:+ 2791:t 2788:d 2785:) 2782:t 2779:, 2774:x 2769:( 2764:u 2759:= 2754:x 2749:d 2728:B 2703:w 2697:v 2669:, 2666:) 2662:B 2652:v 2646:( 2637:+ 2633:B 2625:2 2614:= 2611:) 2607:B 2597:w 2591:( 2534:v 2528:v 2509:. 2506:) 2494:v 2490:( 2481:= 2475:t 2445:v 2439:v 2392:, 2389:0 2386:= 2382:B 2374:) 2369:) 2364:B 2356:v 2351:( 2335:t 2326:B 2315:( 2290:B 2284:l 2273:/ 2271:B 2264:, 2251:v 2247:) 2237:l 2230:( 2227:= 2221:t 2218:D 2212:l 2205:D 2188:v 2184:l 2177:v 2168:v 2161:v 2155:v 2149:l 2128:. 2124:v 2119:) 2103:B 2096:( 2092:= 2088:) 2079:B 2073:( 2066:t 2063:D 2059:D 2031:, 2027:v 2011:= 2005:) 1995:v 1991:( 1988:+ 1982:t 1942:. 1939:) 1935:v 1925:( 1921:B 1913:B 1909:) 1899:v 1895:( 1888:v 1884:) 1874:B 1870:( 1867:= 1861:t 1852:B 1804:= 1798:t 1795:D 1788:B 1780:D 1751:. 1746:1 1741:S 1736:d 1729:) 1724:) 1719:B 1711:v 1706:( 1690:t 1681:B 1670:( 1662:1 1658:S 1649:= 1643:t 1640:D 1633:B 1625:D 1588:. 1584:l 1580:d 1573:) 1569:) 1566:t 1563:( 1559:B 1551:v 1546:( 1538:1 1534:S 1517:1 1512:S 1507:d 1498:t 1490:) 1487:t 1484:( 1480:B 1473:) 1470:t 1464:+ 1461:t 1458:( 1454:B 1443:1 1439:S 1428:0 1422:t 1411:= 1405:t 1402:D 1395:B 1387:D 1364:/ 1361:B 1356:D 1330:, 1326:l 1322:d 1315:) 1311:) 1308:t 1305:( 1301:B 1294:t 1284:v 1279:( 1271:1 1267:S 1250:1 1245:S 1240:d 1234:) 1231:t 1225:+ 1222:t 1219:( 1215:B 1207:1 1203:S 1194:= 1189:2 1184:S 1179:d 1173:) 1170:t 1164:+ 1161:t 1158:( 1154:B 1146:2 1142:S 1122:2 1119:S 1113:1 1110:S 1104:1 1101:S 1094:l 1091:d 1082:v 1078:l 1075:d 1071:3 1068:S 1065:d 1059:3 1056:S 1050:1 1047:S 1044:d 1038:1 1035:S 1013:, 1008:3 1003:S 998:d 992:) 989:t 983:+ 980:t 977:( 973:B 965:3 961:S 952:+ 947:2 942:S 937:d 931:) 928:t 922:+ 919:t 916:( 912:B 904:2 900:S 891:+ 886:1 881:S 876:d 870:) 867:t 861:+ 858:t 855:( 851:B 843:1 839:S 827:= 824:0 806:t 800:2 797:S 791:1 788:S 782:3 779:S 773:2 770:S 764:1 761:S 755:2 752:S 734:. 728:t 718:1 713:S 708:d 702:) 699:t 696:( 692:B 684:1 680:S 666:2 661:S 656:d 650:) 647:t 641:+ 638:t 635:( 631:B 623:2 619:S 605:0 599:t 588:= 582:t 579:D 572:B 564:D 547:2 544:S 538:1 535:S 529:2 526:S 516:v 511:t 506:1 503:S 497:v 491:B 482:3 479:S 473:2 470:S 464:1 461:S 432:. 428:) 423:B 415:v 410:( 400:= 394:t 385:B 335:v 331:t 325:/ 323:D 305:, 302:0 299:= 293:t 290:D 283:B 275:D 258:v 234:B 206:. 203:2 200:S 194:1 191:S 185:2 182:S 176:1 173:S 126:) 123:m 121:R

Index

ideal magnetohydrodynamics
electrically conducting fluids
magnetic fields
magnetic Reynolds numbers
Hannes Alfvén
magnetic topology
current sheets
magnetic reconnection
electrical conductivity
Hannes Alfvén
Arkiv för matematik, astronomi och fysik
eddy currents
Nature
ideal magnetohydrodynamic theory
magnetic Reynolds numbers (Rm)
perfect conductor
length scales
Flux tube
Field line

cylinder
orientable
open
material surface
advected
velocity field
advective derivative
ideal magnetohydrodynamics
magnetic induction
magnetic diffusion

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